Method of electrically charging elecrostatic separating devices.



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APPLICATION FILED DEO.27, 1904.

Patented May 14, 1912.

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FRIEDRICH OSCAR SCHNELLE, OF FRANKFORT-ON-THE-I'IAIN, GERMANY.

METHOD OF ELECTRICALLY CHARGING ELECTROSTATIC SEPARATING DEVICES.

Specification ot Letters Patent.

zit'eiitedMay 14, 1912.

Application filed December 27, 1904. Serial No. 238,387.

To all whom, it may concer/i:

lic it ltnown that I, I"itii;oaicii Osoan Sciixizmr.,engineer, residing at i8 Guiollettstrasse, Franlifort--onthe \Iain, German Empire, have invented certain new and useful Improvements in Methods of Electrically Charginfy Electrostatic Separating lication.

'lhis invention relates to a method of elcc- I trically charging electrostatic separating devices for the dry separation or concentration of conuiiimited granular materials, ores, minerals tte.

The object of my the active parts of a charge of constant potential by the employment of apparatus suited for pernument operation and capable of exact regulation.

IIeretofore the static-imichine was considered as practically the only source o.' elec.- ti'icity of constant potential adapted to the special requirements of electro-static separation. It has also been proposed to use the liuhmliortl induction coil as a suitable source of static-.il electricity of high potential hut this apparatus is unsuited for the separating processes to which the present invention especially applies, viz. those which require a uniform charge of constant potential.

i\Iy invention particularly consists in a method of applyingY electricity of periodically chanffing or alternatingr )otential to the particutlar requirements of e cetro-static separation.

I have discovered that, owing to the property of electro-static separatingr devices to act as condensers of electricity, the active parts of Separatois may be charged to a uniform and constant potential and permanently maintained in the statically charged state, by an intermittent or periodic communication of these partseither conductively or inductively-with a suitable source of high potential electricity.

In accordance with this discovery I have found that a source of periodically changingr or alternating potential can be ap lied for this purpose, provided that a periodic communication between the source o energy and the parts to be charged is made in sintable time intervals, viz. at moments when the potential of the respective generator poles is of the desired value and has the saine sign.

invention is to maintain the separating device at l l l i i and Provided with hubs, I: if.

One way by which this periodic communication may be ellected is illustrated in the annexed drawing, showing the electric apparatus and its connections, partly inperspective, and in part diagruinmatically.

)l represents a magneto-electric generator driven by any suitable `source of power by means of belt aiid pulley,-as showngfor other stiitahle gear.' Y

A are collector rings mounted u )on the machine shaft and connected by brushes l5 B' and wires I, L' to the primary winding of the transformer 'Il rl`he secondary winding of the transformer is connected to the insulated conductors C C placed parallel to the insulated axle D which is coupled with the machine sha ft ll'.

li l' are two rotating collector arms mounted upon the axle l) at an angle ot' ISO" The hubs i' are connected by means of contact lsprings (fr G' and wires Il Il with the opposing poles- I l' of a static separator, as indicated by l X l.

'l`he operation of this apparatus will be readily understood from the above description.

Ieriodie or alternatingr current is generated by the machine M, and transformed to a suitably high potential b v the transformer T. The secondary terminals C C' ot' the transformer being alternately connected h v the synchronous pole. changing collectors I. Ii' to the corresponding parts I I' of the separator X transmit to the latter electric charges of like sign and like (mean) potential. 'l`he individual charges thus transmitted to the opposite poles of the separator are ondensed upon the respective surfaces. thus bringing their potential to the required intensity and keeping the charge up constantly at this value. Since the opposing "pole surfaces of the sepa` rator are sulliciently far apart from each other to vrt-.vent disruptive discharges the individual charges. continuously transmitted at each half revolution of the axle D, only representa veiasmall t iiantity of electricity', sufficient to replenish tlie small amount carried oil continuously by the material (dry comminuted ores. &c.) under treatment and due to imperfection of the insulation of the charged parts of the separating machine.

lVhile the apparatus described illustrates the method of simultaneously charging the opposing parts of the separator by putting them in direct communication with the bichanging devices shown and described.

IV at I claim is:

I. rl`lie method of maintaining a working charge at substantially constant potential of the desired value on the actiije part of an electrostatic separator, which consists in establishing said working charge thereon, and during the period that tlic cliiirge is exercising its separating effect, maintaining the charge at substantially constant potential by the periodic transmission of fractional charges from a source of electrical energy having a potential which does not substantially exceed the desired potential of the charge; substantially as described.

2. The method of maintaining a working charge at substantially constant potential of the desired value on the active part of an electrostatic separator, which consists in establishing said during the period that the charge is exercising its separating effect, inaintainin the charge at substantially constant potential by the periodic transmission of fractional charges from a source of electrical energy of periodically changing potential which does not snbstaiitially exceed the desired potential of the charge, such fractional charges being synchronously collected during transmission; substantiall as described.

3. 'I`lie method of electrically charging the active parts of an electrostatic separator and maintaining the charge at substantially constant potential of the desired v alue, which consists in establishing sucli charge, and eriodically establishing communication etween a source of periodically changing potential and the parts to be charged at moments when the potential of the respective working charge thereon, and

poles of the source is of the same sign as the parts to be charged and does not substantially exceed the desired potential of the charge; substantially as described.

4. The method of electrically charging the active parts of an electrostatic separator and maintaining the charge' at substantially constant potential of the desired value, which consists in establishing such a charge, generating a periodically changing potential of relatively low value, trans orming said po tential to increase its value and periodically establishing communication between the transformer and the parts to be charged at moments when the potential of the desired value of the respective poles of the transformer-is of the saniesign as the )arts to be charged anddbes not substant'ia the desired' potential of the charge; tially as described.

5. The method of electrically charging the active parts of an electrostatic separator and maintaining the charge at substantially con stant potential of the desired value, which consists in generating a periodically changing potential of relatively low value, transforming said potential to increase it to a value which does not substantially exceed the desired potential of the charge, rectifying said potential, and conducting the rectified charges to the active parts of the separator; substantially as described.

6. rl`he method of electrically charging the active parts of an electrostatic separator and maintaining the charge at snbstaiitially constant potential of the desired value, which consists in establishing a working charge of constant potential for the active parts of the separator, and periodically supplying to said active arts small increments of charge correspon infir substantially to the disctiiarge; snbstantia ly as described.

Iii testimony, that I claiiii the foregoing as my invention, I have signed my name in presence of two witnesses, this 14th day of December 1904.

FRIEDRICH OSCAR SCHNELLE.

substanlvitnesses:

JEAN GRUND, Cam. GRUND.

ly 'exceed in Patent No. 14,028,4

them in direct communication with the bi:

polar commutator E E', the invention is by no means limited to this special 'modus operandi'. Thus only one condenser element such as I may be put in direct communication (either conductively or inductively) with the select-ing or rectifyine` device while the other pole may be grounded.

In general it is to be understood that the present invention does not refer to any special type of separator and is not limited to the special kind of generating and pole changing devices shown and described.

`What I claim is:

1. The method of maintaining a working charge at substantially constant potential of the desired -value on the actifs partuof an electrostatic separator, avhichconsists in-es tablishingsaid working charge thereon, and during the period that the charge is exercising its separat-inw effect, maintaining the charge at substantially constant potential by the periodic transmission of fractional charges from a sourceof electrical energy having a potential which does not substantially exceed the desired potential of the charge; substantially as described.

2. The method of maintaining a working charge at substantially constant potential of the desired value on the active part of an electrostatic separator, which consists in establishing said working charge thereon, and' during the period that the charge is exercising its separating effect, maintaining the charge at substantially constant potential by the periodic transmission of fractional charges from a source of electrical energy of periodically changing potential which does not substantially exceed the desired potential of the charge, such fractional charges being synchronously collected during transmission; substantially as described.

3. The method of electrically charging the active parts ot' an electrostatic separator and maintaining the charge at substantially constant potential of the desired v alue, which consists in establishing such charge, and eriodically establishin communication etween a source of periodically changing potential and the parts to be charged at moments when the potential of the respective and thatithegsai Se aratinv Devices au' error a ears in the rinted sl'eclication re uirincr coi-I- a i i 'i "Hi fo y lreetioii as follow Pagetiline 6.

BEST AVAILABLE copy poles of the source is of the same sign as the parts to be charged and does not substantially exceed the desired potential of the charge; substantially as described.

4. The method of electrically charging the active parts of an electrostatic separator and maintaining the cliarge'at substantially constant potential of the desired value, which consists in establishing such a charge, generating a periodically changing potential of relatively low value, trans orming said potential to increase its value and periodically establishing communication v between the transformer and the parts to be charged at moments when the potential of the desired value of the respective poles of the trans- `formeris of the samesign as the parts to be chareed a`iid.'...dofes'.l not. substantially lexceedv the desii'ed' potential of the charge; substantially as described.

5. The method of electrically charging the active parts of an electrostatic separator and maintaining the charge at substantially constant potentialof the desired value, which consists in generating a periodically changing potential of relatively lou value, transforming said potential to increase it to a value which does not substantially exceed the desired potential of the charge, rectifying said potential, and conducting the rectified charges to the act-ive parts of thc separator; substantially as described.

6. The method of electrically charging the active parts of an electrostatic separator and maintaining the charge at substantially constant potential of the desired value, which consists in establishing a working charge of FRIEDRICH OSCAR SCHNELLE.

lVitnesses:

JEAN GRUND, yCani. GRUND.

[t is hereby certified that in Letters Patent No. 1,026,464, granted May 14, 1912,

many, for an improvement.iiifhhlethods of Elefitrically Charging-Electrostatic fthe desired value .i

iii' tha.

ero It upon the application of Friedrich Oscar Schnelle, of Frankfort-on-thefvlaini1 Gerr- 'i .i

[t is hereby certified that in Letters Patent N0. 1,026,464, granted May 14, 1912, upoh the application of Friedrich Oscar Schnelle, of Frankfort-onthe-Main, Ger: inauy, for nn irn'rnovernent,.in4 Methods of Electriculljr Charging Electrostatic Separating Devices, unv error eppeare'in the printed specification requiring correction us followerFedeQli-nes-ffetrikeoht'therorde ffotithe desired vuluef efre'adfwith his correction there-in" that.

'-rctiorn 4ln Letters Patent 

